If you are really interested in the reasons for V1/VR splits, maybe Boeing produce an equivalent to the Airbus "Getting to grips with
aircraft performance".
Some time back, I can remember using performance charts that displayed both V1min and V1max, but guidance from some quarter (I can't remember whether it was JAR or CAA) was to have SOP geared towards being 'GO Minded' and subsequent revisions to the paper performance only displayed V1min.
In the Airbus document "2.4.3.3. MTOW limited by three limitations" gives the reasons for having a range of V1. While there are some aspects of the required factors that are different for the Airbus fly-by-wire, the overall subject is just as relevant to other manufacturers/types.
Airbus Performance Optimization appendix read and enjoy!